Potentiometer device



Buy M, E946. R. F. MALLINA POTENTIOMETER DEVICE Filed May 50, 194A- 2Sheets-Sheet l July i6; i946. R. F. MALLHNA POTENTIOMETER DEVICE FiledMay 50, 1944 2 Sheets-Sheet 2 fam/6.3'

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Patented July 16, 1946 POTENTIOMETER DEVICE Rudolph F. Mallina, Hastingson Hudson, N. Y.,

assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y.,a corporation of New York Application May 30, 1944, Serial No. 538,084

(Cl. 2G1-55) 6 Claims. l 1

This invention relates to potentiometer devices.

The object of this invention is the provision of a potentiometer whichwill be cheap to manufacture and in which electrical connections betweenthe different operative parts of the device are effected in a simple andpositive manner.

In the drawings,

Fig. 1 is a top assembly View;

Fig. 2 is an elevation view shown partly. in vertical section taken online 2 2 of Fig. 1;

Fig. 3 is a partial view. in vertical section showing two slip rings andconnecting wire brushes enlarged with one of the slip rings connectingwith its connecting screws;

Fig. 4 is a top view of one of the discs used in the construction sliprings.

Fig. 5 is a cross-sectional view of the disc shown in Fig. 4 taken inline 5 5 of that gure; and,

Fig. 6 is a diagrammatic View showing the electrical connections betweenthe different cooperative conducting elements of the potentiometer.

In the potentiometer of this invention, a base in the form of asubstantially circular casting II) shown in Figs. 1 and 2 is providedfor mounting a plurality of stationary concentrically disposed coils II,I2, I3, I4 and I5 and a rotatable shaft I6. On this shaft are mounted insuperposed relation to each other a plurality of slip rings rI, r2, r3,11,75, r6, r1, T8, 19,1'I0 and rII, each of which consists of twodish-shaped discs di and d2 best seen in Figs. 3, 4 and 5 anddiagrammatically in Fig, 6. These discs when assembled in pairs formperipheral V-shaped grooves for engagement with conducting brushes inthe form of resilient wires wI, w2, w3, wd, w5, w, w1, w8, wil, wI andwII respectively, thus forming a two-point contact with these discs.

The slip rings rl, r2, r3, etc., thus formed are insulated from ametallic sleeve I9 itted on shaft I5 b-y a sleeve 2li of any suitableinsulating material and the slip rings are positioned in spaced relationto each other by similar insulating rings ZI also serving for insulatingshields in the form of metallic discs 22 from the slip rings rl, r2, r3,etc.

The shields 22 are electrically connected to f each other and to sliprings r2, by a rod 23 shown in Figs. 2 and 6 engaging holes drilled inthe shield and in one of the discs forming the slip rings r2 with apress t adjustment, the slip ring r2 being engaged by the wire brush w2as shown in Figs. 2 and 6, the wire brush being connected to a groundterminal 24.

On metallic sleeve I9 is mounted a disc 25 serving for securing aplurality of pairs of arms as AI-A2, BI-BZ, CI-C2, DI-DZ and EI-EZ onthe free ends of which are mounted the-pairs of wipers A3, B3, C3, D3and E3, respectively, each pair of wipers collectively engaging theresistance coils in the following order: wipers A3 engaging the coil I5,wipers B3 engaging the coil I4, wipers C3 engaging the coil lf3, wipersD3 engaging the coil I2 and wipers E3Yengaging the coil II. lhe armsAI-A2, BI,-B2, CI -C2, etc., are insulatively secured to the disc 25' bythe clamping action of a 'plurality of similar screws 26 engagingsimilarly screw-threaded holes in a ring 2'I, insulated from the 'armsAI-A2, BI-BZ, CI-C2, etc., by a ring 28 and a sleeve 29.

Electrical connections from the pairs of wipers A3, B3, C3, etc., andtheir supporting arms AI-AZ, BI--B2, CI-C2, etc., with their respectivewire brushes wI, w2, w3, wd, w, etc., are eiected by screws sl, s2, s3,s4, $5, s6, S7, sil, S9 and SIU of different lengths extending throughclearance holes such as CH in the superposed slip rings rII, TIS, r9,etc., in clearance holes such as CH2 in the shield 2?. and in clearanceholes such as CH3 in the insulating spacer rings 2|, in engagement withthe screw-threaded holes as h in the discs dI of their respectivelyassociated slip rings in the following order: screw sI as shown in Fig.6 connecting with the slip ring rl, screw s2 with slip ring r3, screw s3with slip ring r4, screw s4 with slip ring f5, screw S5 ywith slip ringT5, screw sii with slip ring r1, screw sl' with slip ring f8, screw S8with slip ring r9, screw S9 with slip ring TID and screw sIIl with slipring rII. The slip rings, the insulating rings 2I and the shield 22 areheld collectively in assembled relation with the disc 25 and insulatingsleeve 20 by the clamping action of a nut 30 bearing against a metallicwasher 3l and an insulating washer 32, the latter bearing against theslip ring rl. The metallic sleeve I9 is secured to the shaft IS by aclamping ring 33 engaging the screw-threaded portion of the sleeve I9which is slotted longitudinally as at 35 forming prongs forced againstthe shaft I6 by the tightening of a screw 34.

The wir@ brushes wl, w2, w3, wd, etc., are molded in a bank ofinsulating material tted 0n a stud `4I laterally extending from andthreadedly engaging a projection 42 formed with the base Il), the bank40 being held securely on the stud 4I by the tightening effect of ascrew 43 following the proper tensioning of wire brushes wl, w2, w3,etc., on their respectively associated slip rings rl, r2, r3, etc.,while the contact pressure of wipers A3, B3, C3, etc., is convenientlyeffected by the'simple twisting or bending their supporting arms lil-A2, Bl-B2, etc.

What is claimed is:

1. In a potentiometer, a mounting, a plurality of resistance coilssecured to said mounting, a. pair of wipers for each of said resistancecoils frictionally engaging the latter, means for moving said pairs ofwipers on said resistance coils collectively, a. contact for each ofsaid wipers, means electrically connecting said wipers to said contactsrespectively, and stationary brushes frictionally engaging saidcontacts.

2. In e, potentiometer, a mounting, a plurality o! circular resistancecoils secured to said mounting. a shaft journaled in said mountingpositioned concentric to said resistances, a plurality of arms mountedon said shaft, wiper elements carried by said arms engaging saidresistances, a plurality of slip rings mounted on said shaft, means electrically connecting said wipers to said slip rings individually, and astationary brush associated with each of said slip rings.

3. In a potentiometer, a plurality of resistance coils arranged inconcentric relation to each other, a pair of wipers for engaging each ofsaid coils, a rotatable shaft for moving said wipers collectively onsaid coils, a plurality of slip rings mounted in superposed relation onsaid shaft, one of said slip rings for each of said wipers, and meanselectrically connecting each of said wipers to each of said slip ringsin said superposed relation.

4. In a potentiometer, a plurality of resistance coils arranged inconcentric relation to each other, a pair of wipers for engaging each ofsaid coils, a rotatable shaft for moving said wipers collectively onsaid coil, a slip ring for each of said wipers, each of said slip ringshaving a contact surface of V-shaped cross-section, and a brush ofcircular cross-section engaging said groove for contact at two points insaid groove.

5. In a potentiometer, a plurality of concentrically disposed resistancecoils, a rotatable shaft disposed concentric tosaid coils, a pluralityof wiper members carried by said shaft for engaging said coils, sliprings and shield discs mounted in a pile-up arrangement on said shaft,insulating means serving as spacer members between said slip rings andsaid shield discs, means electrically connected to said shield discscollectively to one of said slip rings and a plurality of other meanselectrically connecting each of said Wipers to each of the other of saidslip rings in said pile-up.

6. In a potentiometer, a plurality of concentrically disposed resistancecoils, a rotatable shaft disposed concentric to said coils, a metallicsleeve mounted on said shaft, a disc carried by said sleeve, a pluralityof wipers insulatedly mounted on said disc, an insulating sleeve fittedon said metallic sleeve concentric thereto, a plurality of slip ringsand shield discs insulated from each other and fitted over saidinsulating sleeve in a pile-up arrangement, means for securing saidpile-up to said metallic sleeve and means for securing said metallicsleeve to said shaft.

RUDOLPH F. MALLINA.

